| Abstract
| - Because a micelle is constituted by rather weak hydrophobic intermolecular interaction, molecular motion inthe micelle is quite active and quick. This rapid molecular motion in a long threadlike micelle formed in anaqueous solution of a cationic detergent, cetyltrimethylammonium bromide (CTAB), with sodium salicylate(NaSal), was examined by dielectric relaxation analysis. We found broadly distributed dielectric spectra inthe frequency range from 106 to 109 s-1 due to molecular motion of micelle-forming molecules, which wereproportional in magnitude to the concentration of CTAB. The fastest relaxation mode, around 109 s-1, isattributed to the rotation of an ionic pair formed by a headgroup of a cetyltrimethylammonium cation, CTA+,and a salicylate anion, Sal-, as observed in the spherical micelle of CTAB in aqueous solution. On the otherhand, a slow relaxation mode, around 107 s-1, is caused by the localized distribution of ions, CTA+ and Sal-,in the threadlike micelle after the lifetime of the ionic pair.
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